Chemical Preservation of Urine Sediment for Phase-Contrast Microscopic Examination

Objective. Prospective studies were conducted to test the hypothesis that infants unlikely to have serious bacterial infections (SBI) can be accurately identified by low risk criteria. Methods. Febrile infants (rectal T ≥ 38°C) ≤60 days of age were considered at low risk for SBI if they met the following criteria: 1) appear well; 2) were previously healthy; 3) have no focal infection; 4) have WBC count 5.0-15.0 x 109 cells/L (5000-15 000/mm3), band form count≤ 1.5 x 109 cells/L (≤1500/mm3), ≤10 WBC per high power field on microscopic examination of spun urine sediment, and ≤5 WBC per high power field on microscopic examination of a stool smear (if diarrhea). The recommended evaluation included the culture of specimens of blood, cerebrospinal fluid, and urine for bacteria. Outcomes were determined. The negative predictive values of the low risk criteria for SBI and bacteremia were calculated. Results. Of 1057 eligible infants, 931 were well appearing, and, of these, 437 met the remaining low risk criteria. Five low risk infants had SBI including two infants with bacteremia. The negative predictive value of the low risk criteria was 98.9% (95% confidence interval, 97.2% to 99.6%) for SBI, and 99.5% (95% confidence interval, 98.2% to 99.9%) for bacteremia. Conclusions. These data confirm the ability of the low risk criteria to identify infants unlikely to have SBI. Infants who meet the low risk criteria can be carefully observed without administering antimicrobial agents.

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Comparison of the diagnostic performance of two automated urine sediment analyzers with manual phase-contrast microscopy

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2019-0919 ◽

2020 ◽

Vol 58 (2) ◽

pp. 268-273 ◽

Cited By ~ 3

Author(s):

Dietmar Enko ◽

Ingeborg Stelzer ◽

Michael Böckl ◽

Brigitta Derler ◽

Wolfgang J. Schnedl ◽

...

Keyword(s):

Phase Contrast ◽

Diagnostic Performance ◽

White Blood Cells ◽

Reference Method ◽

Phase Contrast Microscopy ◽

Diagnostic Agreement ◽

Urine Sediment ◽

Contrast Microscopy ◽

Renal Tubular ◽

Roche Diagnostics

AbstractBackgroundRecently, several manufacturers have launched automated urinalysis platforms. This study aimed to compare the diagnostic performance of the UF-5000 (Sysmex Corporation, Kobe, Japan) and the cobas® u 701 (Roche Diagnostics, Rotkreuz, Switzerland) urine sediment analyzers with manual phase-contrast microscopy as the reference method.MethodsA total of 195 urine samples were analyzed on both automated platforms and subjected to manual microscopic examination. Agreement was assessed by Cohen’s kappa (κ) analysis. Sensitivities and specificities were calculated.ResultsThe agreement of the UF-5000 with manual microscopy was almost perfect (κ > 0.8) for red (RBC) and white blood cells (WBC), renal tubular epithel cells, hyaline casts, bacteria (BACT) and yeast (YLC), substantial (κ = 0.61–0.80) for squamous epithel cells (SEC) and pathologic casts, and moderate (κ = 0.41–0.60) for transitional epithel cells. The cobas® u 701 showed substantial agreement (κ = 0.61–0.80) for WBC, moderate agreement (κ = 0.41–0.60) for hyaline casts, and fair agreement (κ = 0.21–0.40) for RBC, SEC, non-squamous epithel (NEC), pathologic casts, BACT and YLC. The UF-5000 sensitivities ranged between 98.5% for RBC and 83.3% for pathological casts. The cobas® u 701 showed sensitivities between 83.0% for WBC and 31.6% for YLC.ConclusionsThe UF-5000 (Sysmex) analyzer showed a better diagnostic agreement with manual phase-contrast microscopy compared to the cobas® u 701 (Roche) module. The Sysmex platform showed reliable results for urine sediment analysis. However, pathological samples should be verified with manual microscopy.

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